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SOPHISTICATED SYSTEM WILL CLEAR POLLUTANTS FROM ROADWAY RUNOFF
ON FOOTHILL-SOUTH TOLL ROAD EXTENSION
IRVINE, Calif. (September 12, 2007) -- The Foothill/Eastern Transportation Corridor Agency has developed a sophisticated roadway runoff plan for the 16-mile Foothill-South (241) Toll Road extension to ensure that all runoff from pavement is treated and cleaned of pollutants before it reaches local streams and ultimately the ocean.
The system will also treat runoff along two miles on Interstate 5 that currently goes untreated.
Key features of the plan include a system that separates roadway runoff from natural runoff coming from upstream areas and another that collects and funnels all roadway runoff into treatment devices along the route.
Fifty-three culverts are planned to carry the water from the upstream areas underneath the roadway. This system also ensures that the natural flow of sediment to the beaches and ocean remains consistent and unchanged, including to the popular Trestles surfing beach.
The culverts will maintain the natural flow of sediments that nurture the beach,” said Scott Taylor, senior vice president of RBF Consulting, which participated in the design of the system.
Contaminated runoff from the pavement on the route will be collected and funneled into several treatment areas adjacent to the road. They include 10 water collection basins, called detention basins, to hold the runoff; three sand filters to capture trash and contaminants, and seven swales or depressed areas with vegetation to allow pollutants to settle out before the clean water is released at a controlled rate into the creeks.
During large storms, the initial runoff containing the majority of pollutants will be treated first, and then the subsequent rainwater will be diverted off the road to ensure that the treatment basins do not flood and flush out pollutants already captured in the basins.
Other features include measures to prevent pollution by controlling its sources, including minimizing disturbances to vegetation and replanting slopes as quickly as possible to control runoff and erosion.
“The systems are state-of-the-art, but we know how to operate and maintain them. We’ve incorporated the best practices that have been tested on other state highways,” Taylor said.
“Overall, the system is designed to mimic the original hydrology of the area as much as possible, and minimize the impacts to a level of insignificance,” he said.
COMPLETION OF THE 241 TOLL ROAD
The Foothill/Eastern Transportation Corridor Agency is responsible for the planning, design, construction and operation of the 241 Toll Road. The final 16 miles of the toll road, called Foothill-South, is the final piece in Orange County’s planned 67-mile toll road network. The project has been the subject of regional planning efforts for more than 20 years.
A conceptual highway alignment, then named the Foothill Transportation Corridor, was placed on Orange County’s Master Plan of Arterial Highways in 1981. The highway was identified to alleviate anticipated traffic demand from new housing developments in south and east Orange County and as a regional highway alternative to the I-5 Freeway between San Diego and Los Angeles counties.
TCA and other state and federal agencies have analyzed dozens of alternatives during the 20-year environmental review process. A decision on a preferred alternative was made by the Foothill/Eastern Board of Directors in February 2006. The chosen alignment balances the needs of the traveling public, while providing the most environmentally sensitive road possible. Through years of unprecedented planning, the alignment maximizes open space and wildlife connectivity, avoids sensitive habitat areas and takes no homes or businesses. Completing the 241 Toll Road will provide a free-flowing alternative to I-5, improve public safety, and reduce traffic on the I-5 freeway and city streets.
ABOUT TCA
The Toll Roads are operated by the Transportation Corridor Agencies, two joint powers authorities formed by the California state legislature in 1986 to plan, finance, construct, and operate Orange County's 67-mile public toll road system. More info: www.thetollroads.com
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